High-Efficiency Micro-Pillar Infrared Light Emitting Diode Arrays for Infrared Scene Projection

Here we propose to enhance the wallplug efficiency of cascaded superlattice light emitting diodes (C-SLEDs) from 6.1 Å III-V semiconductor materials by micro-structuring. At low temperatures, C-SLEDs have already achieved greater than 1% quantum efficiency when operating in the mid-wave infrared (MWIR). Preliminary electromagnetic simulations indicate that micro-structuring enhances efficiency at least 10-15x through improved light extraction and the Purcell effect. The micro-structured C-SLED can be fabricated simply with photolithography, and is compatible with fabrication of large scale, flip-chipped infrared LED (IRLED) arrays for thermal scene projectors (TSPs). Higher efficiency IRLEDs in the MWIR and the long-wave infrared (LWIR) are expected to help greatly with problematic thermal management in IRLED-based TSPs, where large amounts of heat are generated by low efficiency devices. High power, high efficiency IRLEDs will also be very attractive for use in optical based sensors of gasses such as carbon dioxide and methane.